Ultraviolet absorption spectrum of gaseous HOCl
The UV absorption spectrum of gaseous HOCl was investigated in the wavelength region 240 to 390 nm by using a dynamic HOCl source. Substantial quantities of HOCl were produced compared to two species (Cl/sub 2/O, ClO/sub 2/) that are spectral interferences in the wavelength region of interest. Thirteen experimental absorption spectra were analyzed by the statistical method of factor analysis. This analysis revealed that two major components were contributing to the total absorbance in each spectrum and that these two components accounted for 99.97% of all variance in the data. Mass spectra were simultaneously recorded with the absorption spectra by a quadrupole mass spectrometer that was calibrated for HOCl, Cl/sub 2/, Cl/sub 2/O, ClO/sub 2/, and other species. The two components in the absorption spectra were identified as Cl/sub 2/ and HOCl containing trace levels of ClO/sub 2/. The isolated Cl/sub 2/ and HOCl/ClO/sub 2/ spectral curves were obtained from a spectral-isolation factor analysis and quantified by using the Cl/sub 2/ spectrum as an internal standard. Atmospheric photolysis constants averaged over 24 h were calculated as a function of altitude from these cross sections and those currently recommended for atmospheric modeling. The calculated j values from the cross sections generated in this work predict a shorter photolysis lifetime for HOCl above 28 km. This results in a 6 to 19% decrease in the predicted HOCl diurnal average concentration in the altitude region 28 to 34 km, respectively, compared to the concentrations predicted by the currently recommended cross sections.
- Research Organization:
- Univ. of Colorado, Boulder
- OSTI ID:
- 6962546
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 90:22
- Country of Publication:
- United States
- Language:
- English
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ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
HYPOCHLOROUS ACID
ABSORPTION SPECTROSCOPY
MASS SPECTROSCOPY
EXPERIMENTAL DATA
OZONE
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA
DATA
ELECTROMAGNETIC RADIATION
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
NUMERICAL DATA
RADIATIONS
SPECTRA
SPECTROSCOPY
400201* - Chemical & Physicochemical Properties
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)